Despite the defeat, which is Shabab's second loss of the 2016-2017 season, it remained on top of the table with 39 points after 19 rounds.
Shabab took the lead just after the half-hour mark when its Brazilian striker Loks slammed in a goal, his eighth of the season. However, Arouba fought back and levelled the scores soon after the break with Zomana struck and then national team striker Mohammed Taqi blasted home the winner with five minutes left.
The only other loss for Shabab this season was on October 27 when it lost 0-2 to Sohar at the Seeb Sports Stadium.
Dhofar is hot on the heels of Shabab as it beat His Majesty's Cup winner Saham 2-1 at the Sohar Sports Complex to trail the leader by just two points. National team attacking midfielder Qasim Said and Lawson scored for the nine-time winner.
Arouba's win over Shabab kept it in third place with 34 points, while Al Nahda's solitary-goal win over Sohar at Al Buraimi Sports Complex took it to fourth place with 29 points. Leading OPL scorer Frank got the hosts the win with his 14th goal of the season.
Sohar is fifth with 29 points, while defending champion and nine-time champion Fanja suffered 0-2 defeat at the hands of Al Nasr, its second successive loss, to be stuck at sixth place with 26 points.
In other matches played on Friday, Muscat beat bottom-placed Jalan 2-0, Al Khabourah and Al Suwaiq played out a 2-2 draw, and Oman hammered Rustaq 5-1 in a battle between relegation-threatened teams.
Standings [after 19 rounds]: 1 Al Shabab (39 pts), 2 Dhofar (37), 3 Al Arouba (34), 4 Al Nahda (29), 5 Sohar (29), 6 Fanja (26), 7 Al Nasr (25), 8 Al Suwaiq (24), 9 Muscat (24), 10 Saham (24), 11 Al Khabourah (21), 12 Oman (19), 13 Al Rustaq (16), 14 Jalan (13).